We should specify that we talk about horizontal scalability of physical machines — that’s the only problem. CPUs on one machine will be handled by one VM, no matter what the number of those is. node = machine. To begin, I can say that 30-60 nodes you get out of the box (vanilla OTP installation) … Read more
What are the essentials of distributed real-time systems? A distributed real-time system composes two challenging sets of properties which are imposed by the problem domain or the solution domain (or both.) Distributed A distributed system links a number of independent computing entities with local properties by way of a communication mechanism. As a consequence, algorithms … Read more
Almost any scientific code — finite differences, finite elements, etc. Which kind of leads to the circular answer, that any distributed program which doesn’t easily map to MapReduce would be better implemented with a more general MPI model. Not sure that’s much help to you, I’ll downvote this answer right after I post it.
You missed something in step 7. When C processes accept 100:b it sets its state to C(100:b,100). By accepting a value the node is also promising to not accept earlier values. Update. I’ve been thinking about this all month because I knew the above answer was not absolutely correct. What’s more I looked through several … Read more
As programmers, we like to believe we are smart people, so it’s hard to admit that something is too big and complex to even think about all at once. But for a large-scale software project it’s true, and the sooner you acknowledge your finite brain capacity and start coming up with ways to simplify the … Read more
In latest version, you can run your script with: ./jmeter-server -Djava.rmi.server.hostname=xxx.xxx.xxx.xxx Replace xxx.xxx.xxx.xxx with this server’s IP address, i.e., the IP address that the controlling jmeter machine will use to connect to this server.
I didn’t read the article, so I can only speculate what he can mean exactly, but as he gives ESB as an example against microservices and ZeroMQ as an example for micro services I hope my speculation will be pretty exact: One of the ideas of Unix (and Linux) is to build small independent applications … Read more
If you can use something like CRDT, do so. You should get much better performance. It also enables interesting use cases such as working offline and then merging later. However it is not always possible to design things such that a CRDT will work for you. In that case, paxos can solve the hard problems … Read more
Regarding question 1, Redis is an in-memory store with some persistency capabilities. All your dataset should fit in memory. A single instance is therefore limited by the maximum memory of your server. Now, you can also shard the data to several Redis instances, running on multiple servers. Provided you have the budget for it, it … Read more
Probably the lightest-weight solution for real-time log watching is to use Dancer’s shell in concurrent mode with tail -f: dsh -Mac — tail -f /var/log/apache/*.log The -a is for all machine names that you’ve defined in ~/.dsh/machines.list The -c is for concurrent running of tail The -M prepends the hostname to every line of output.